Airplane rib



March 26, 1940.

K. SCHMIDT AIRPLANE RIB Filed April 17, 1939 ATTORNEY Patented/Mar. 26, 1940 OFFICE AmrLANE am Y 'Karl schmidt, United stata;4 Navy l Appupttpn April 11,1939, serial No. assez?.

1 Claim.

"1 (Grantea under thev act Ao1' Maren s. 1883, as

amended April 3o, 192s; s'zo o. G. 757) This invention relates to airplane ribs and it has a particular relation to the capstrip portions thereof to which the envelope or covering is secured.

5 The principal object of this invention is the provision of an airplane wing rib which is so constructed 4that the fabric covering may be at- 1 tached thereto continuously throughout the en= tire length of the rib, thus avoiding localized strains and insuring that the covering is stretched tightly with evenly distributed tension so that the Yfull strength of the cover fabric may be developed.

Another Aobject of the invention is the provision of an airplane wing rib and cooperating cover fastening device by means of which the cover may be secured in position without rupturing the same and when thus secured will present a smooth-cambered surface of high aerodynamic eiliciency. l

` With these and other objects in view, as Well as other advantages that may be incident to the use of the improvements, the invention consists in the parts and combinations thereof hereinafter set forth and claimed, with the understanding that the several necessary elements constituting the same may be varied in proportion and arrangement without departing from the nature and scope of the invention, as defined in the appended claim.

In order to make the invention more clearly understood, there are shown in the accompanying drawing, means for carrying the invention into practical use, -without limiting the improvements in their useful application to the particular construction, which, for the purpose of explanation, have been made the subject of illustration.

In the accompanying drawing:

Fig. 1 is a diagrammatic side elevational view of an airplane wing rib constructed in accordance with the invention;

Fig. 2 is an enlarged transverse sectional view through the upper capstrip of the rib taken on line 2-2 of Fig. l;

Fig. 3 is a similar view taken on line 3-3 of Fig. 1; and Fig. 4 is a fragmentary view of the tool employed in securing the covering in position.- .o Referring to the drawing, an airplane wing rib constructed in accordance with the invention is shown as comprising upper and lower capstrings I0 and respectively, the same being joined at the leading edge of the rib by an integral curved portion I2 and at the trailing edge thereof by a gusset plate I3. The capstrips Il) and VII are connected together at intermediate points by diagonal'bracing members, indicated at Il, and' the several vribsso constructed are secured to fore-and-aft longitudinal beams I5 and I6 re- 5 spectively. e

The capstrips I0 and each comprise an inner vertical flange I1 and outer diverging flanges |8 formed with rounded edges I8 (Fig. 2),` which latter have a strip of some smooth material 20, 1|)

such as Cellophane, glued thereto to reduce friction with the wing fabric; A plurality of studs 2| are threaded into the bottom of the depression formed by the iianges I8 at spaced intervals and are formed with tapered or pointed outer i5 ends 22 and with apertures 23. A fabric covering or envelope 24 is stretched over the capstrip and flexed downwardly into the depression between the flanges I8 by a suitable tool, the pointed ends 22 of the studs 2| piercing the fabric between the 20 warp and Woof threads thereof, thereby avoiding rupturing the covering. The tool employed for this purpose preferably embodies a cylindrical barrel or tube 25 (Fig. 4) having an internal diameter suiiicient to nt over thel ends of the 2g studs 2| and formed with a notch 26 at its lower end adapted tol register with the apertures 23 when it is in its lowermost position. A reinforcing tape 21 is cemented to the covering 24 prior to the securing operation and is also pierced 30 by the pointed ends of the studs 2| when the covering is exed into the depression. When this operation is completed a securing wire 28 is threaded through the apertures 23 of the studs so as to provide a continuous fastening means ex- 35 tending the entire length of the rib. In practice this wire will extend entirely around the lrib 'and its ends twisted together or otherwise secured at the trailing endl of the rib. This securing wire also serves to prevent the studs from unscrew- 40 ing. Thereafter, a tape 29 is cemented to the covering 24 so as to bridge the depression 'formed where the covering is flexed inwardly and to cover the outer ends of the studs 2|, thus'l providing a smooth, unbroken cambered surface for the wing of high aerodynamic efficiency.

'mie leading edge I2 of the rib where they curve abruptly are flattened, as shown in Fig. 3', and the inneniianges are cut away, as indicated at 30 (Fig. 1). Also, the upper capstrip i0 may 50 have its inner ange portion |1 cut away at intervals, as indicated at 3| in order to reduce weight. The inner flange I1 of the lower capstrip is, however, left intact to provide the nec essary compressive strength. 5|

very eiilcient cover attaching means is provided and one which will permit of the quick and easy removal of the covering for replacement or repairs with minimum4 injury to the covering.

It will be understood that the above description and accompanying drawing comprehend only the general and preferred embodiment of the lnvention, and' that various other changes in the construction, proportion and arrangement of the parts may be made by those skilled in the art without departing from the nature and scope of the invention as deiined in the appended claim.

The invention described herein may be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon] or therefor. Y

I claim:

An airplane a capstrip having an inwardly extending web portion and outwardly extending diverging ilanges forming a longitudinal depression, a plurality of spaced studs fixed in said depression and having vapertures extending therethrough, a.y fabric covering extending over said capstrip and exed into said depression, said 'studs having tapered outer ends adapted to pierce said covering between the threads of the weave thereof to prevent the rup-A ture ofsaid covering and a securing wire extending along the bottom of said depression above said covering and through the apertures in said studs for securing said covering to said capstrip within the surface of the wing. t

wing rib construction comprising' 

